The present invention relates to an all-around vehicle antenna apparatus mounted on a vehicle such as an automobile and, more particularly, to an improvement in an antenna apparatus constituted mainly of a slot antenna provided on a vehicle window.
In a conventional windowpane antenna apparatus provided on a vehicle window, a long, narrow thin-film conductor having a predetermined pattern, which is to be formed on the window surface, is used as an antenna element. This antenna element is connected to a transmitter/receiver set via a feeder.
Since, in the windowpane antenna apparatus, a metal window frame serves as a grounding conductor, its shape has influence upon antenna characteristics. Usually the shape of a metal window frame greatly varies from vehicle to vehicle; therefore, even though an antenna element is formed with great precision so as to have a given size and a given shape, the antenna characteristics are greatly varied with the type of a vehicle on which the antenna element is to be mounted, with the result that a desired antenna characteristic cannot be obtained appropriately. To mount the above windowpane antenna apparatus on a vehicle, it is necessary to form a pattern for each antenna element in order to match the shape of a window frame of every vehicle, thus causing a drawback of making it difficult to manufacture the antenna element, and increasing in manufacturing costs.